scholarly journals Accuracy of a Novel SARS-CoV-2 Antigen-Detecting Rapid Diagnostic Test from Standardized Self-Collected Anterior Nasal Swabs

2021 ◽  
Vol 10 (10) ◽  
pp. 2099
Author(s):  
Bilgin Osmanodja ◽  
Klemens Budde ◽  
Daniel Zickler ◽  
Marcel G. Naik ◽  
Jörg Hofmann ◽  
...  
Keyword(s):  
Primary Endpoint ◽  
Point Of Care ◽  
World Health Organisation ◽  
Ease Of Use ◽  
Alternative Methods ◽  
World Health ◽  
Healthcare Personnel ◽  
Sample Collection ◽  
Rt Pcr ◽  
Nasal Swabs

Background Antigen-detecting rapid diagnostic tests (Ag-RDT) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) offer new opportunities for the quick and laboratory-independent identification of infected individuals for control of the SARS-CoV-2 pandemic. Despite the potential benefits, nasopharyngeal sample collection is frequently perceived as uncomfortable by patients and requires trained healthcare personnel with protective equipment. Therefore, anterior nasal self-sampling is increasingly recognized as a valuable alternative. Methods We performed a prospective, single-center, point of care validation of an Ag-RDT using a polypropylene absorbent collector for standardized self-collected anterior nasal swabs. Real-time polymerase chain reaction (RT-PCR) from combined oropharyngeal/nasopharyngeal swabs served as a comparator. Primary endpoint was sensitivity of the standardized Ag-RDT in symptomatic patients with medium or high viral concentration (≥1 million RNA copies on RT-PCR for SARS-CoV-2). Results Between 12 February and 22 March 2021, 388 participants were enrolled. After exclusion of 9 patients for which no PCR result could be obtained, the novel Ag-RDT was evaluated based on 379 participants, of whom 273 were symptomatic and 106 asymptomatic. In 61 samples from symptomatic patients with medium or high viral load (≥1 million RNA copies), the sensitivity of the standardized Ag-RDT was 96.7% (59/61; 95% confidence interval (CI): 88.7–99.6%) for the primary endpoint. In total, 62 positive Ag-RDT results were detected out of 70 RT-PCR positive individuals, yielding an overall sensitivity of 88.6% (95% CI: 78.7–94.9%). Specificity was 99.7% (95% CI: 98.2–100%) in 309 RT-PCR negative individuals. Conclusions Here, we present a validation of a novel Ag-RDT with a standardized sampling process for anterior nasal self-collection, which meets World Health Organisation (WHO) criteria of ≥80% sensitivity and ≥97% specificity. Although less sensitive than RT-PCR, this assay could be beneficial due to its rapid results, ease of use, and suitability for standardized self-testing.

scholarly journals Diagnostic accuracy of a novel SARS-CoV-2 antigen-detecting rapid diagnostic test from standardized self-collected anterior nasal swabs

2021 ◽  
Author(s):  
Bilgin Osmanodja ◽  
Klemens Budde ◽  
Daniel Zickler ◽  
Marcel G. Naik ◽  
Jörg Hofmann ◽  
...  
Keyword(s):  
Primary Endpoint ◽  
Point Of Care ◽  
High Viral Load ◽  
Ease Of Use ◽  
Healthcare Personnel ◽  
Sample Collection ◽  
Rt Pcr ◽  
Self Testing ◽  
Nasal Swabs ◽  
Potential Benefits

AbstractBackgroundAntigen-detecting rapid diagnostic tests (Ag-RDT) for SARS-CoV-2 offer new opportunities for the quick and laboratory-independent identification of infected individuals for control of the SARS-CoV-2 pandemic. Despite the potential benefits, nasopharyngeal sample collection is frequently perceived as uncomfortable by patients and requires trained healthcare personnel with protective equipment. Therefore, anterior nasal self-sampling is increasingly recognized as a valuable alternative.MethodsWe performed a prospective, single-center, point of care validation of an Ag-RDT using a polypropylene absorbent collector for standardized self-collected anterior nasal swabs. Real-Time Polymerase Chain Reaction (RT-PCR) from combined oropharyngeal/nasopharyngeal swabs served as a comparator. Primary endpoint was sensitivity of the standardized Ag-RDT in symptomatic patients with medium or high viral concentration (≥ 1 million RNA copies on RT-PCR for SARS-CoV-2).ResultsBetween February 12 and March 22, 2021, 388 participants were enrolled. After exclusion of 9 patients for which no PCR result could be obtained, the novel Ag-RDT was evaluated based on 379 participants, of which 273 were symptomatic and 106 asymptomatic. In 61 samples from symptomatic patients with medium or high viral load (≥ 1 million RNA copies), the sensitivity of the standardized Ag-RDT was 96.7% (59/61; 95%CI: 88.7-99.6%) for the primary endpoint. In total, 62 positive Ag-RDT results were detected out of 70 RT-PCR positive individuals, yielding an overall sensitivity of 88.6% (95%CI: 78.7-94.9%). Specificity was 99.7% (95%CI: 98.2-100%) in 309 RT-PCR negative individuals.ConclusionHere, we present a validation of a novel Ag-RDT with a standardized sampling process for anterior nasal self-collection, which meets WHO criteria of ≥80% sensitivity and ≥97% specificity. Although less sensitive than RT-PCR, this assay could be beneficial due to its rapid results, ease of use, and suitability for standardized self-testing.(Funded by Drägerwerk AG & Co. KGaA, Lübeck, Germany; ClinicalTrials.gov number NCT04698993)

scholarly journals Head-to-head comparison of SARS-CoV-2 antigen-detecting rapid test with self-collected anterior nasal swab versus professional-collected nasopharyngeal swab

2020 ◽  
Author(s):  
Andreas K. Lindner ◽  
Olga Nikolai ◽  
Franka Kausch ◽  
Mia Wintel ◽  
Franziska Hommes ◽  
...  
Keyword(s):  
Point Of Care ◽  
Rapid Test ◽  
High Viral Load ◽  
Ease Of Use ◽  
Healthcare Personnel ◽  
Nasopharyngeal Swab ◽  
Swab Sample ◽  
Rt Pcr ◽  
Percent Agreement ◽  
Accuracy Study

AbstractBackgroundTwo antigen-detecting rapid diagnostic tests (Ag-RDTs) are now approved through the WHO Emergency Use Listing procedure and can be performed at the point-of-care. However, both tests use nasopharyngeal (NP) swab samples. NP swab samples must be collected by trained healthcare personnel with protective equipment and are frequently perceived as uncomfortable by patients.MethodsThis was a manufacturer-independent, prospective diagnostic accuracy study with comparison of a supervised, self-collected anterior nose (AN) swab sample with a professional-collected NP swab sample, using a WHO-listed SARS-CoV-2 Ag-RDT, STANDARD Q COVID-19 Ag Test (SD Biosensor), which is also being distributed by Roche. The reference standard was RT-PCR from an oro-/nasopharyngeal swab sample. Percent positive and negative agreement as well as sensitivity and specificity were calculated.ResultsAmong the 289 participants, 39 (13.5%) tested positive for SARS-CoV-2 by RT-PCR. The positive percent agreement of the two different sampling techniques for the Ag-RDT was 90.6% (CI 75.8-96.8). The negative percent agreement was 99.2% (CI 97.2-99.8). The Ag-RDT with AN sampling showed a sensitivity of 74.4% (29/39 PCR positives detected; CI 58.9-85.4) and specificity of 99.2% (CI 97.1-99.8) compared to RT-PCR. The sensitivity with NP sampling was 79.5% (31/39 PCR positives detected; CI 64.5-89.2) and specificity was 99.6% (CI 97.8-100). In patients with high viral load (>7.0 log 10 RNA SARS-CoV2/swab), the sensitivity of the Ag-RDT with AN sampling was 96% and 100% with NP sampling.ConclusionSupervised self-sampling from the anterior nose is a reliable alternative to professional nasopharyngeal sampling using a WHO-listed SARS-CoV-2 Ag-RDT. Considering the ease-of-use of Ag-RDTs, self-sampling and potentially patient self-testing at home may be a future use case.

scholarly journals Sample collection and transport strategies to enhance yield, accessibility, and biosafety of COVID-19 RT-PCR testing

2021 ◽  
Vol 70 (9) ◽  
Author(s):  
Padmapriya Banada ◽  
David Elson ◽  
Naranjargal Daivaa ◽  
Claire Park ◽  
Samuel Desind ◽  
...  
Keyword(s):  
Diagnostic Yield ◽  
Point Of Care ◽  
Sampling Strategy ◽  
Sample Collection ◽  
Rt Pcr ◽  
Non Invasive ◽  
Viral Transport ◽  
Combined Use ◽  
Nasal Swabs ◽  
Polymerase Chain

Introduction. Non-invasive sample collection and viral sterilizing buffers have independently enabled workflows for more widespread COVID-19 testing by reverse-transcriptase polymerase chain reaction (RT-PCR). Gap statement. The combined use of sterilizing buffers across non-invasive sample types to optimize sensitive, accessible, and biosafe sampling methods has not been directly and systematically compared. Aim. We aimed to evaluate diagnostic yield across different non-invasive samples with standard viral transport media (VTM) versus a sterilizing buffer eNAT- (Copan diagnostics Murrieta, CA) in a point-of-care diagnostic assay system. Methods. We prospectively collected 84 sets of nasal swabs, oral swabs, and saliva, from 52 COVID-19 RT-PCR-confirmed patients, and nasopharyngeal (NP) swabs from 37 patients. Nasal swabs, oral swabs, and saliva were placed in either VTM or eNAT, prior to testing with the Xpert Xpress SARS-CoV-2 (Xpert). The sensitivity of each sampling strategy was compared using a composite positive standard. Results. Swab specimens collected in eNAT showed an overall superior sensitivity compared to swabs in VTM (70 % vs 57 %, P=0.0022). Direct saliva 90.5 %, (95 % CI: 82 %, 95 %), followed by NP swabs in VTM and saliva in eNAT, was significantly more sensitive than nasal swabs in VTM (50 %, P<0.001) or eNAT (67.8 %, P=0.0012) and oral swabs in VTM (50 %, P<0.0001) or eNAT (58 %, P<0.0001). Saliva and use of eNAT buffer each increased detection of SARS-CoV-2 with the Xpert; however, no single sample matrix identified all positive cases. Conclusion. Saliva and eNAT sterilizing buffer can enhance safe and sensitive detection of COVID-19 using point-of-care GeneXpert instruments.

scholarly journals Diagnosis of SARS-Cov-2 Infection by RT-PCR Using Specimens Other Than Naso- and Oropharyngeal Swabs: A Systematic Review and Meta-Analysis

Diagnostics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 363
Author(s):  
Vânia M. Moreira ◽  
Paulo Mascarenhas ◽  
Vanessa Machado ◽  
João Botelho ◽  
José João Mendes ◽  
...  
Keyword(s):  
Systematic Review ◽  
Clinical Performance ◽  
Point Of Care ◽  
Meta Analysis ◽  
High Sensitivity ◽  
Nasopharyngeal Swab ◽  
Sample Collection ◽  
Rt Pcr ◽  
Oropharyngeal Swab ◽  
Nucleic Acid Assays

The rapid and accurate testing of SARS-CoV-2 infection is still crucial to mitigate, and eventually halt, the spread of this disease. Currently, nasopharyngeal swab (NPS) and oropharyngeal swab (OPS) are the recommended standard sampling techniques, yet, these have some limitations such as the complexity of collection. Hence, several other types of specimens that are easier to obtain are being tested as alternatives to nasal/throat swabs in nucleic acid assays for SARS-CoV-2 detection. This study aims to critically appraise and compare the clinical performance of RT-PCR tests using oral saliva, deep-throat saliva/posterior oropharyngeal saliva (DTS/POS), sputum, urine, feces, and tears/conjunctival swab (CS) against standard specimens (NPS, OPS, or a combination of both). In this systematic review and meta-analysis, five databases (PubMed, Scopus, Web of Science, ClinicalTrial.gov and NIPH Clinical Trial) were searched up to the 30th of December, 2020. Case-control and cohort studies on the detection of SARS-CoV-2 were included. The methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS 2). We identified 1560 entries, 33 of which (1.1%) met all required criteria and were included for the quantitative data analysis. Saliva presented the higher accuracy, 92.1% (95% CI: 70.0–98.3), with an estimated sensitivity of 83.9% (95% CI: 77.4–88.8) and specificity of 96.4% (95% CI: 89.5–98.8). DTS/POS samples had an overall accuracy of 79.7% (95% CI: 43.3–95.3), with an estimated sensitivity of 90.1% (95% CI: 83.3–96.9) and specificity of 63.1% (95% CI: 36.8–89.3). The remaining index specimens could not be adequately assessed given the lack of studies available. Our meta-analysis shows that saliva samples from the oral region provide a high sensitivity and specificity; therefore, these appear to be the best candidates for alternative specimens to NPS/OPS in SARS-CoV-2 detection, with suitable protocols for swab-free sample collection to be determined and validated in the future. The distinction between oral and extra-oral salivary samples will be crucial, since DTS/POS samples may induce a higher rate of false positives. Urine, feces, tears/CS and sputum seem unreliable for diagnosis. Saliva testing may increase testing capacity, ultimately promoting the implementation of truly deployable COVID-19 tests, which could either work at the point-of-care (e.g. hospitals, clinics) or at outbreak control spots (e.g., schools, airports, and nursing homes).

Roles and strategies of international humanitarian organisations in handling the Liberia Ebola outbreak

2019 ◽  
Author(s):  
Jia Bainga Kangbai ◽  
Ahmed Alameldeen
Keyword(s):  
Emergency Preparedness ◽  
Ebola Virus ◽  
Virus Disease ◽  
World Health Organisation ◽  
West African ◽  
World Health ◽  
Healthcare Personnel ◽  
African Countries ◽  
History Of ◽  
Public Health Emergency Preparedness

Abstract Background In Early August 2014, the World Health Organisation declared an Ebola Virus Disease (EVD) outbreak in the region of West Africa. The West African EVD outbreak was the largest, most severe, and complex in the nearly four-decade history of this disease. The management of EVD cases in Liberia was similar to the other affected West African countries. Methods We reviewed the method and strategies used by some of the international humanitarian organisations in handling the 2013-2016 Ebola outbreak in Liberia. This report is a collection of personal field experiences in Liberia as well as personal interviews of healthcare personnel working for some of these international organisations working on the Ebola emergency in Liberia. Findings Medecins Sans Frontieres (MSF) was the first humanitarian NGO to deploy medical staff to the field in Liberia during the 2013-2016 EVD outbreak. MSF staffs were already operating in Liberia even before the declaration of the outbreak in August 2014.Conclusions The slow response by the international humanitarian organisations to lend their support in bringing the EVD outbreak to and exhibited the fear the international community have for deadly infectious diseases more than armed conflicts.Recommendations We recommend regularly training in public health emergency preparedness for third world countries that are highly susceptible to health emergencies such as Ebola outbreak to help prepared them ahead of such outbreak.

scholarly journals Improving Risk Assessments by Sanitary Inspection for Small Drinking-Water Supplies—Qualitative Evidence

Resources ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 71 ◽  
Author(s):  
Katherine Pond ◽  
Richard King ◽  
Jo Herschan ◽  
Rosalind Malcolm ◽  
Rory Moses McKeown ◽  
...  
Keyword(s):  
Drinking Water ◽  
Assessment Tool ◽  
World Health Organisation ◽  
Ease Of Use ◽  
World Health ◽  
Remedial Action ◽  
Water Supplies ◽  
Qualitative Evidence ◽  
Operations And Maintenance

Small drinking-water supplies face particular challenges in terms of their management. Being vulnerable to contamination but often not monitored regularly nor well-maintained, small drinking-water supplies may pose consequences for health of users. Sanitary inspection (SI) is a risk assessment tool to identify and manage observable conditions of the water supply technology or circumstances in the catchment area that may favour certain hazardous events and introduce hazards which may become a risk to health. This qualitative research aimed to identify the strengths and weaknesses of the SI tool as published by the World Health Organisation to inform a review and update of the forms and to improve their robustness. The study identified a number of benefits of the approach, such as its simplicity and ease of use. Challenges were also identified, such as potential for inconsistencies in perception of risk between inspectors, in interpreting questions, and lack of follow-up action. The authors recommend a revision of the existing SI forms to address the identified challenges and development of complementary advice on possible remedial action to address identified risk factors and on basic operations and maintenance.

scholarly journals Loop-Mediated Isothermal Amplification as Point-of-Care Diagnosis for Neglected Parasitic Infections

2020 ◽  
Vol 21 (21) ◽  
pp. 7981
Author(s):  
Catalina Avendaño ◽  
Manuel Alfonso Patarroyo
Keyword(s):  
Neglected Tropical Diseases ◽  
Point Of Care ◽  
Low Cost ◽  
High Specificity ◽  
World Health Organisation ◽  
Isothermal Amplification ◽  
World Health ◽  
Parasitic Infections ◽  
River Blindness ◽  
Loop Mediated Isothermal Amplification

The World Health Organisation (WHO) has placed twenty diseases into a group known as neglected tropical diseases (NTDs), twelve of them being parasitic diseases: Chagas’ disease, cysticercosis/taeniasis, echinococcosis, food-borne trematodiasis, human African trypanosomiasis (sleeping sickness), leishmaniasis, lymphatic filariasis, onchocerciasis (river blindness), schistosomiasis, soil-transmitted helminthiasis (ascariasis, hookworm, trichuriasis), guinea-worm and scabies. Such diseases affect millions of people in developing countries where one of the main problems concerning the control of these diseases is diagnosis-based due to the most affected areas usually being far from laboratories having suitable infrastructure and/or being equipped with sophisticated equipment. Advances have been made during the last two decades regarding standardising and introducing techniques enabling diagnoses to be made in remote places, i.e., the loop-mediated isothermal amplification (LAMP) technique. This technique’s advantages include being able to perform it using simple equipment, diagnosis made directly in the field, low cost of each test and the technique’s high specificity. Using this technique could thus contribute toward neglected parasite infection (NPI) control and eradication programmes. This review describes the advances made to date regarding LAMP tests, as it has been found that even though several studies have been conducted concerning most NPI, information is scarce for others.

scholarly journals assayM: a web application to monitor mutations in COVID-19 diagnostic assays

2020 ◽  
Author(s):  
Raeece Naeem ◽  
Arnab Pain
Keyword(s):  
Web Application ◽  
Pcr Primers ◽  
World Health Organisation ◽  
Virus Genome ◽  
World Health ◽  
Rt Pcr ◽  
Diagnostic Assays ◽  
Link Type ◽  
Specificity And Sensitivity ◽  
R Shiny

AbstractSummaryReverse Transcriptase – Polymerase Chain Reaction (RT-PCR) is the gold standard as diagnostic assays for the detection of COVID-19 and the specificity and sensitivity of these assays depend on the complementarity of the RT-PCR primers to the genome of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since the virus mutates over time during replication cycles, there is an urgent need to continuously monitor the virus genome for appearances of mutations and mismatches in the PCR primers used in these assays. Here we present assayM, a web application to explore and monitor mutations introduced in the primer and probe sequences published by the World Health Organisation (WHO) or in any custom-designed assay primers for SARS-CoV-2 detection assays in globally available SARS-CoV-2 genome datasets.Availability and implementationassayM is available on https://grafnet.kaust.edu.sa/assayM as a web application and also as an open-source R shiny application, downloadable from https://github.com/raeece/[email protected]

scholarly journals Evaluation of sample collection and transport strategies to enhance yield, accessibility, and biosafety of COVID-19 RT-PCR testing

2021 ◽  
Author(s):  
Padmapriya Banada ◽  
David Elson ◽  
Naranjargal Daivaa ◽  
Claire Park ◽  
Samuel Desind ◽  
...  
Keyword(s):  
Sampling Methods ◽  
Diagnostic Yield ◽  
Sampling Strategy ◽  
Sample Collection ◽  
Rt Pcr ◽  
Viral Inactivation ◽  
Viral Transport ◽  
Nasal Swabs ◽  
Polymerase Chain ◽  
Transport Buffer

ABSTRACTSensitive, accessible, and biosafe sampling methods for COVID-19 reverse-transcriptase polymerase chain reaction (RT-PCR) assays are needed for frequent and widespread testing. We systematically evaluated diagnostic yield across different sample collection and transport workflows, including the incorporation of a viral inactivation buffer. We prospectively collected nasal swabs, oral swabs, and saliva, from 52 COVID-19 RT-PCR-confirmed patients, and nasopharyngeal (NP) swabs from 37 patients. Nasal and oral swabs were placed in both viral transport media (VTM) and eNAT™, a sterilizing transport buffer, prior to testing with the Xpert Xpress SARS-CoV-2 (Xpert) test. The sensitivity of each sampling strategy was compared using a composite positive standard. Overall, swab specimens collected in eNAT showed superior sensitivity compared to swabs in VTM (70% vs 57%, P=0.0022). Direct saliva 90.5%, (95% CI: 82%, 95%), followed by NP swabs in VTM and saliva in eNAT, was significantly more sensitive than nasal swabs in VTM (50%, P<0.001) or eNAT (67.8%, P=0.0012) and oral swabs in VTM (50%, P<0.0001) or eNAT (56%, P<0.0001). Saliva and use of eNAT buffer each increased detection of SARS-CoV-2 with the Xpert test; however, no single sample matrix identified all positive cases.

scholarly journals Detection of trace arsenic in drinking water: challenges and opportunities for microfluidics

2021 ◽  
Author(s):  
Nevetha Yogarajah ◽  
Scott S. H. Tsai
Keyword(s):  
Drinking Water ◽  
World Health Organisation ◽  
Arsenic Contamination ◽  
Ease Of Use ◽  
World Health ◽  
Arsenic Detection ◽  
Routine Monitoring ◽  
Challenges And Opportunities ◽  
Sensitivity And Selectivity ◽  
Economic Constraints

Arsenic contamination of drinking water is a major global problem, with contamination in Bangladesh deemed most serious. Although the current World Health Organisation (WHO) maximum contamination limit (MCL) for arsenic in drinking water is 10 μg L−1, due to practical and economic constraints, the standard limit in Bangladesh and many other developing nations is 50 μg L−1. We propose that an ideal arsenic sensor, designed for routine monitoring, will have five essential qualities: sensitivity and selectivity for arsenic; speed and reliability; portability and robustness; reduced health and environmental risks; and affordability and ease of use for local technicians. It is our opinion that many of these characteristics can be accentuated by microfluidic systems. We describe candidate colorimetric, electrochemical, biological, electrophoretic, surface-sensing, and spectroscopic methods for arsenic detection; and comment on their potential for portable microfluidic adaptation. We also describe existing developments in the literature towards the ultimate creation of microfluidic total analysis systems (μTASs) for arsenic detection. The fundamental purpose of this review is to highlight the need for better portable arsenic contamination detection, and describe how microfluidic technology may be developed to address this need.

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